Various types of cardiovascular catheters are known in the prior art. Such prior art cardiovascular catheters include certain coronary artery catheters which are specifically sized and configured to be percutaneously inserted and advanced through the vasculature into the ostia of the left or right main coronary artery. Such coronary artery catheters include (a) coronary angiography catheters which are typically used to inject radiographic contrast medium directly into the coronary vasculature and (b) coronary guiding catheters which are typically used to guide the advancement of a guidewire and/or a second catheter (e.g. a balloon angioplasty catheter) into a specific coronary artery.
The primary application for coronary "guiding" catheters is presently in the performance of percutaneous transluminal coronary angioplasty (PTCA) procedures. Such PTCA procedures routinely involve the initial percutaneous insertion of a 0.35-inch guidewire into a peripheral artery (e.g. a femoral artery) with subsequent advancement of the distal tip of the guidewire into the thoracic aorta. A coronary guiding catheter is then advanced over the preinserted guidewire to a point near the origin of the coronary artery at which point the 0.035-inch guidewire is removed. The distal tip of the "guiding" catheter is then inserted within the desired (i.e. right or left) coronary ostium. A smaller diameter balloon angioplasty catheter is then advanced over a smaller diameter (typically 0.10-0.18 inches), through the lumen of the guiding catheter, to a point where the balloon is within the distal aspect of the guiding catheter. The guidewire is then further advanced out of and beyond the distal tip of the guiding catheter such that the distal tip of the guidewire passes into, through, or around the occlusive coronary lesion to be treated is located. Once the guidewire has been passed through or across the occlusive lesion, the operator then further advances the balloon dilation catheter over the guidewire to a point where the balloon has become positioned at the stenotic lesion. The balloon dilatation angioplasty procedure is then accomplished by repetitive inflation and deflation of the balloon. After the angioplasty has been completed, the balloon catheter and guidewire are withdrawn, leaving the coronary guiding catheter in place. Roentgenographic contrast medium may then be injected through the coronary guiding catheter to determine whether the angioplasty procedure has successfully restored patency of the diseased vessel.
Those skilled in the art will appreciate that, during the insertion and manipulation of an angioplasty catheter, the coronary guiding catheter through which the angioplasty catheter is inserted must provide sufficient guidance and "backup" to prevent bending or kinking of the angioplasty catheter as it is advanced and/or manipulated through the stenotic lesion. The guide catheter must provide sufficient stability of position to enable the balloon catheter to follow the guidewire despite tortuosity of the coronary artery and the severity of the target lesion. Also, it is desirable that the distal tip of the guiding catheter be directly inserted into the main coronary artery in a manner that will not interfere with subsequent manipulation or torquing of the guidewire and/or angioplasty catheter into a desired branch of such main coronary artery. Additionally, it is desirable that the "guiding" catheter be constructed in a manner that will prevent the distal tip of the catheter from creeping or inadvertently advancing an inordinate distance into the main coronary artery as such "creeping" or inadvertent advancement of the guiding catheter tip may interfere with or complicate subsequent extraction and withdrawal of the guiding catheter.
Examples of cardiovascular catheters which are purported to be sized and/or configured and/or constructed for insertion into a coronary artery are included in the following U.S. Pat. Nos. 4,739,768 (Engelson); 4,385,635 (Ruiz); 4,813,930 (Elliott); 4,759,748 (Reed); 4,817,613 (Jaraczewski et al.); 4,586,923 (Gould et al.); 4,636,346 (Gold et al.); 4,033,331 (Guss et al.); 4,784,639 (Patel); 4,117,836 (Erikson); 4,822,345 (Danforth); 3,935,857 (Co); 4,516,972 (Samson); 4,547,193 (Rydell); 4,747,840 (Ladika et al.); 4,777,951 (Cribier et al.); and 4,808,164 (Hess). Although many types of coronary artery catheters exist in the prior art, no single coronary artery catheter has been found to be universally optimal for use as a "guiding" catheter in the performance of all coronary angioplasty procedures. Accordingly, there remains a need in the art for improved coronary guiding catheters for use in guiding guidewires, balloon angioplasty devices and the like into a specific coronary artery.